Rodentia, and probably out of relatives of the Subungulata. The order of _Insect Eaters_ (Insectivora) is a very ancient group, and is next akin to the common extinct primary form of the Deciduata, as well as to the Semi-apes of the present day. It has probably developed out of Semi-apes which were closely allied to the Long-footed Lemurs (Macrotarsi) of the present day. It is separated into two orders, Menotyphla and Lipotyphla; the Menotyphla are probably the older of the two, and are distinguished from the Lipotyphla by possessing an intestinal cœcum, or typhlon. The Menotyphla include the climbing Tupajas of the Sunda Isles, and the leaping Macroscelides of Africa. The Lipotyphla are represented in our country by shrew mice, moles, and hedgehogs. The Insectivora, in the formation of their jaws and their mode of life, are nearly akin to Carnivora, but are, on the other hand, by their discoplacentas and by their large seminal vesicles, allied to Rodents. It is probable that the order of _Rapacious animals_ (Carnaria) developed out of a long since extinct branch of Insectivora, at the beginning of the Eocene period. It is a natural group, very rich in forms, but still of very uniform organization. The Rapacious animals are sometimes also called Girdle-placentals (Zonoplacentals), although the Pseudo-hoofed animals (Chelophora), in the same way, also deserve this designation. But as the latter, in other respects, are more closely allied to the Rodentia than to Carnaria, we have already discussed them in connection with the former. Animals of prey are divided into two, externally very different, but internally very closely related, sub-orders, namely, Land animals of prey and Marine animals of prey. The _Land animals of prey_ (Carnivora) comprise bears, dogs, cats, etc., whose pedigree can be approximately guessed at by means of many extinct intermediate forms. The _Marine animals of prey_, or _Seals_ (Pinnipedia), comprise sea bears, sea dogs, sea lions, and walruses. Although marine animals of prey appear externally very unlike land animals of prey, yet by their internal structure, their jaw and their peculiar girdle-shaped placenta, they are very nearly akin to them, and have evidently originated out of a branch of them, probably out of a kind of weasel (Mustelina). Even at the present day the fish otters (Lutra), and still more so the sea otters (Enhydris), present a direct form of transition to Seals, and clearly show how the bodies of land Carnivora are transformed into the shape of a Seal, by adaptation to an aquatic life, and how the steering fins of marine rapacious animals have arisen out of the legs of the former. The latter consequently stand in the same relation to the former as do the Whales to Hoofed animals among the Indeciduata. In the same way as the river-horse at present stands midway between the extreme branches of oxen and sea oxen, the sea otter still forms a surviving intermediate stage between the widely